A recently released report says dredged material from Greenwich Harbor could safely be dumped in a Long Island Sound disposal site, a senior U.S. Army Corps of Engineers official said.

But Edward O'Donnell, chief of the navigation section for the corps' New England District, cautioned that it still has to review a report.

"We haven't completed our suitability study from our reanalysis unit to determine if it is appropriate to go to Long Island Sound," he said.

An initial review of the study, by Woods Hole Group Inc., of East Falmouth, Mass., however, appears to show the material could be safely disposed of, he said.

"It identified various levels of contaminants in the sediment and some biological testing. From what I understand it passed the biological testing and can go to Long Island Sound," O'Donnell said.

In January, the Army Corps of Engineers sampled and tested the material clogging the harbor, a silt-filled channel that hasn't been dredged from 1968. The federal study cost nearly $500,000.

The harbor channel is 1.4 miles long with an authorized depth of 12 feet at low tide. A 2007 study by the Corps found that depth had dropped to 7 feet.

The channel's northern end begins where town ferries are docked near Arch Street, extends to the south where the Indian Harbor Yacht Club sits at the tip of the peninsula at the end of Steamboat Road.

Two years ago, the Army Corps estimated it would cost $12 million to dredge 250,000 cubic yards from the harbor.

It now estimates that approximately 300,000 cubic yards would be dredged.

O'Donnell said the project's price can vary greatly, in large part driven by disposal costs for dredged material. If it is taken out to a Sound disposal area, it is much cheaper than at a land-based site, in large part because of transportation costs, he said.

The Town of Greenwich saw how stark the differences were in a $1.9 million 2009 project near Grass Island where 24,700 cubic yards of material was dredged.

Two thousand cubic yards was discovered to be contaminated with heavy metals and could not be dumped in the Sound. That had to be handled separately at a cost of $160 per cubic yard. The contaminated material was taken by barge to New Haven where it was mixed with cement to thicken it before it was finally trucked to Meriden to be dumped as landfill in a tire pond.

The remaining 22,700 cubic yards cost $55 per cubic yard to have it dumped in the Sound.

The corps would be responsible for dredging costs.

That's where the situation becomes tricky, O'Donnell said, because Greenwich is in competition with commercial ports. Those ports, whether they are smaller, such as Bridgeport and New Haven, or large ones like New York City, get first call on any federal money due to their importance for the economy, he said.

"A harbor like this has basically zero tonnage reported," O'Donnell said about Greenwich.

First Selectman Peter Tesei said ensuring boaters can enjoy and safely navigate the town's waterways is an important economic plus for the town. It also is a concern for more than just boaters, he said.

"It is not just the boating community. I think there is a recognition that waterfront property is valuable and that has been confirmed by the sales of properties," he said. "I think it is a critical part of our overall infrastructure that is sometimes taken for granted."

The town supports anything that will improve water quality, Tesei said, as he pointed out the work done on its waste water system and trying to stem stormwater runoff.